In Japanese Laid-Open Patent Publication No. 2007-060489 (hereinafter referred to as “JP2007-060489A”), a vehicle-mounted receiver apparatus 100 including a navigation device 102 is disclosed. With the vehicle-mounted receiver apparatus 100, route guidance is carried out using the navigation device 102, and emergency information (disaster information, etc.) contained in a digital broadcast is displayed on a monitor 103 through the navigation device 102.
According to JP2007-060489A, upon determining the emergency information contained within the digital broadcast, at first, it is judged whether or not the value of an emergency alert broadcast flag (emergency information flag) in the received data is 1. If the value of the emergency information flag is 1, then data that is tagged with the emergency information is extracted and used. Stated otherwise, with JP2007-060489A, the contents of the delivered data per se are confirmed to determine whether or not the data should be used as the emergency information.
Further, in a third embodiment of JP2007-060489A, a configuration is disclosed in which, using position information of the vehicle and position information of a disaster occurrence point while route guidance is being performed (i.e., while using route information), the navigation device 102 determines a priority at which the warning information is displayed. Moreover, as a modification of the third embodiment, for example, concerning emergency information of the occurrence of an artificial or unnatural disaster such as a terrorism event or the like, it is described that a broadcast station may be allowed to determine the display priority.